1. Field of the Invention
This disclosure relates to 3-dimensional (3D) printing of objects and, more particularly, to techniques for storing and retrieving data embedded into the surface of a 3D printed object.
2. Description of the Related Art
Technology currently available and well known provides for 3-dimensional (3D) printing of physical 3D objects. Such objects can be the shape of any physical creation conceived by man, from something as simple as a geometric shape like a ball or cube to something as complex as a replica of an intricate trestle bridge, a statue by the artist Michelangelo, or a representation of an exotic animal. As is typical of creations that result from human effort, it is desirable to associate information with such creations, such as the name of the entity, person or company that created the object, the name of entity, person or company, that printed the object, a creation date, a name for the object, or any other information that entity would like to have associated with the 3D object. It is typically desired that such information be as permanently associated with the object as possible. One way humans convey information is by writing. Written information communicates facts (also called data) that are acquired at a given point in time and then conveyed to others by an arrangement of symbols. Symbols can include, for example, numeric characters such as 1, 2, 3, . . . etc., alphabetic characters such as A, B, C . . . etc., which examples are representative of Arabic numerals and Latin letters. Many other kinds of letters and numeric characters are also known and used that are based on different languages, such as Chinese, to name just one other language.
One technique used to associate written information so that it is presented in combination with a physical object, is to convey the information by use a label having written characters printed thereon. One type of label designed to function particularly well in a digital environment is a barcode. A barcode is a type of label which is easy for a machine to create and simple for a machine to reliably read. A barcode, like any other label, is an arrangement of symbols that conveys information, such as an identification, to be associated with a physical object. Although the identification of an object can be conveyed by a lengthy description of the object, which will require the use of many symbols, a barcode may be a unique and predefined arrangement of symbols that can be used to convey the identification information with less symbols. Originally, barcodes used spaced parallel lines as symbols, which systematically represent data by varying the widths and spacings of the parallel line symbols. Such barcodes are referred to as linear or one-dimensional (1D) since their varying widths and spacings can be detected by moving an edge detector in a single direction (i.e., 1D) so as to traverse the parallel lines. In the last decade 1D barcodes have evolved into rectangles, dots, hexagons and other geometric patterns arranged in two dimensions (2D). By having two dimensions to present data, more data can be conveyed with a 2D barcode as compared with a 1D barcode. For example, one kind of object identification information that can be in a barcode is called a stock-keeping unit (SKU) number. An SKU number is a unique identifier that is assigned by a business for each distinct product that can be purchased from that business, such as SKU#123456789. Thus, detailed identification information for a physical object can be compactly conveyed by merely providing a barcode that has the SKU number for that physical object.
In order that the barcode identification information (such as an SKU number or other arrangement of information conveying symbols) does not become separated from the physical object, barcodes are typically printed on a label and then attached to the physical object, such as by glue or other adhesive.
Other types of information can be included in a barcode, such as an Expiration date, an Owner, a Universal Resource Locator (URL), a Batch number, a Watermark, a Production date, a Package date, a Serial number, a Weight (kgs/pounds), a Price, a Universal Product Code (UPC), a Revision Number, a Phone Number, or any other information imaginable. The only limit on the amount of information that can be conveyed by a barcode type label is the amount of space on the label in which to write the symbols used to convey the information. Since the size of the label is limited by the size of the product on which it is to be placed, it is always desirable to find a way to improve the amount of information that a label of a limited size, such as a barcode, can carry. Currently one dimensional (1D) and two dimensional (2D) barcodes are ubiquitous elements in modern manufacturing processes and products. Barcodes based on Universal Product Code (UPC) and the “GS1” standards are numeric data used to identify products and allow businesses to track their products from creation to sale.
Most current 1D and 2D barcodes are limited to printing 2D representations directly on an object or on a label and then adhering the label to a surface of the object. Sometimes the 2D representations can be micro-etched on hard surfaces of the object. As previously noted, 2D barcodes provide more information as compared with a 1D barcode because two dimensions of the label are available for writing the symbols that convey the data as compared with one dimension. However, even when 2D surface barcodes are used, the amount of data that can be conveyed is limited by the 2D area of the surface used on which the symbols are written. Additionally, the durability of the data presented by a 2D barcode is low because a surface presentation, such as a label, can be easily damaged (for example by the action of a liquid, such as water, degrading the ink used to print the barcode, or by water degrading the adhesive used to affix the barcode to the surface of the object). Even a 2D barcode presentation that is etched into the surface of an object can be damaged to the point of being partially obscured by being worn away by repeated handling of the object or by exposure of the object to the forces of nature over time. Even furthermore, cryptology and steganography techniques for providing robust data security are unnecessarily limited when using 2D barcodes, since they are limited to techniques that only use two dimensions.